Is Harmonic or Onyx better for AI endpoint control?

Neither is scored on this site. Harmonic describes 2 of four product control types and Onyx 3 on the pages we read, and they differ on 8 recorded facts. Which fits depends on the AI tools people use, your devices, where the work happens and whether you block or guide; the finder checks those.

Which of the two decides on a tool call before it runs?

Harmonic: Partly. Onyx: Matches. Warn or ask: Harmonic Matches, Onyx Matches.

Do Harmonic or Onyx publish prices?

Harmonic: Three named tiers (Explore, Guide, Command) with no prices; a full prompt audit log is an add-on on Guide and Command. Onyx: Not published.

HEAD-TO-HEAD · FACTS ONLY

Harmonic vs Onyx: AI endpoint control facts side by side

Short answer

Harmonic describes 2 of the four product control types on the pages we read and Onyx describes 3; they differ on on-device control. On decisions, Harmonic describes some control over tool calls and Onyx decides on a tool call before it runs. We do not score either; the right choice depends on the AI tools people use, your devices, your current stack and whether you block or guide.

By The Device Desk · Endpoint AI Finder · Published 2026-10-11

Desk research from public vendor pages read on 27 September and 11 October 2026. Profiles follow our published method; we did not run the products.

Vendor pages read September and October 2026 · updated 2026-10-13

Where do their controls sit?

Filled or hatched marker: Harmonic
Dashed teal ring: Onyx, described

DEV Filled marker: described on the product pages we read
DEV Hatched marker: partly described (another component, a narrower scope, or method not detailed)
DEV Dashed marker: not in our sources (it may exist; we did not find it)

The map shows where each product's own pages describe a control, or where your answers point. It is not a measure of how well a product works.

What are the facts, side by side?

Harmonic Security and Onyx Security, from each product's own pages. Differs is computed from recorded statuses, not wording.
Fact	Harmonic	Onyx
Owner	None	None
Positioning	A data protection product for everyday AI use, sold as Explore, Guide and Command, covering browser extensions, desktop apps and CLI tools, MCP gateways and an API.	"The Secure AI Control Plane for the Agentic Era": inline inspection of prompts, tool calls and model responses across browser AI, coding assistants, desktop AI agents, cloud workloads and MCP servers. Based in Tel Aviv and New York.
How it reaches devices	Rolls out through Intune, JAMF, Kandji or Group Policy. Source: Harmonic Security homepage · Read 27 Sep 2026	Endpoint agents, browser extensions, APIs and gateways. Source: Onyx Security: AI security platform · Read 27 Sep 2026
On-device controlDiffers	Partly describedDeployment options include desktop apps and AI agents, rolled out through device management; the on-device component is not described in detail. Source: Harmonic Security pricing (re-read) · Read 11 Oct 2026	DescribedEndpoint agents cover coding assistants and desktop AI agents. Source: Onyx Security: AI security platform · Read 27 Sep 2026
Browser extension	DescribedBrowser extensions are a listed surface, with block, warn or log actions. Source: Harmonic Security homepage · Read 27 Sep 2026	DescribedBrowser extensions cover browser AI. Source: Onyx Security: AI security platform · Read 27 Sep 2026
Network or SSE proxy	Not in our sourcesNot described on the pages we read.	Not in our sourcesNot described on the pages we read.
AI or MCP gateway	DescribedMCP gateways are a listed surface, and Harmonic Command governs at the MCP layer and at the tool surface. Source: Harmonic Security: Command · Read 27 Sep 2026	DescribedGateways and APIs inspect traffic inline. Source: Onyx Security: AI security platform · Read 27 Sep 2026
Names the coding agents it coversDiffers	MatchesThe Guide tier adds desktop AI apps and developer tools, naming Claude Code, GitHub Copilot, ChatGPT Desktop and Microsoft 365 Copilot. Source: Harmonic Security pricing (re-read) · Read 11 Oct 2026	PartlyCovers coding assistants; specific tools are not named on the pages we read. Source: Onyx Security: AI security platform · Read 27 Sep 2026
Decides on a tool call before it runsDiffers	PartlyThe Command tier adds MCP client and server discovery, agent permissions for read, write and execute, and MCP server tool controls. Source: Harmonic Security pricing (re-read) · Read 11 Oct 2026	MatchesInspects every prompt, tool call and model response inline. Source: Onyx Security: AI security platform · Read 27 Sep 2026
Controls what goes into browser AI	MatchesBlock, warn or log on AI use in the browser. Source: Harmonic Security homepage · Read 27 Sep 2026	MatchesCan mask data in browser AI as well as block it. Source: Onyx Security: AI security platform · Read 27 Sep 2026
Rolls out through EDR or device management you runDiffers	MatchesRolls out through Intune, JAMF, Kandji or Group Policy. Source: Harmonic Security homepage · Read 27 Sep 2026	Not in our sources
Can warn or ask instead of only blocking	MatchesWarn is one of three actions, with block and log. Source: Harmonic Security homepage · Read 27 Sep 2026	MatchesFive actions: alert, block, mask, steer or ask. Source: Onyx Security: AI security platform · Read 27 Sep 2026
Can block an agent, tool or action	MatchesBlock is one of three actions. Source: Harmonic Security homepage · Read 27 Sep 2026	MatchesBlock is one of five actions. Source: Onyx Security: AI security platform · Read 27 Sep 2026
Has a watch-only or simulation modeDiffers	MatchesLog is one of three actions, for watching before enforcing. Source: Harmonic Security homepage · Read 27 Sep 2026	PartlyAlert is one of five actions; a simulation mode is not described. Source: Onyx Security: AI security platform · Read 27 Sep 2026
Records who or what took each actionDiffers	Not in our sources	PartlyIntegrates with Okta, Entra and Splunk; separating a person from an agent is not described. Source: Onyx Security: AI security platform · Read 27 Sep 2026
Also covers SaaS, cloud or homegrown AIDiffers	PartlyAn API is listed alongside device surfaces; SaaS or cloud agents are not described. Source: Harmonic Security homepage · Read 27 Sep 2026	MatchesCloud workloads and MCP servers as well as devices. Source: Onyx Security: AI security platform · Read 27 Sep 2026
Has a public price or tiers (vendor site or marketplace)Differs	PartlyNames three tiers (Explore, Guide, Command) on its pricing page, without prices. Source: Harmonic Security: pricing · Read 27 Sep 2026	Not in our sources
Built into	None	None
Works with	None in our sources	Lists CrowdStrike among its integrations. Source: Onyx Security: AI security platform · Read 27 Sep 2026
Price	Three named tiers (Explore, Guide, Command) with no prices; a full prompt audit log is an add-on on Guide and Command. Source: Harmonic Security pricing (re-read) · Read 11 Oct 2026	Not published. Source: Onyx Security homepage · Read 27 Sep 2026

Where do they differ?

On-device control: Harmonic partly describes it; Onyx describes it.
Names the coding agents it covers: Harmonic matches; Onyx partly matches.
Decides on a tool call before it runs: Harmonic partly matches; Onyx matches.
Rolls out through EDR or device management you run: Harmonic matches; Onyx is not in our sources.
Has a watch-only or simulation mode: Harmonic matches; Onyx partly matches.
Records who or what took each action: Harmonic is not in our sources; Onyx partly matches.
Also covers SaaS, cloud or homegrown AI: Harmonic partly matches; Onyx matches.
Has a public price or tiers (vendor site or marketplace): Harmonic partly matches; Onyx is not in our sources.

Choose Harmonic if

Your main risk is employees pasting sensitive data into AI tools and you would rather coach than block
You manage devices with Intune, JAMF, Kandji or Group Policy

Choose Onyx if

You want masking or steering rather than only allow or block
AI use spans the browser, desktop apps, coding tools and cloud workloads

Which limits should you check?

Harmonic

Tier names only, no prices, and the full prompt audit log is an add-on.
An activity record that separates a person from an agent is not described, and prompt injection protection is listed as coming soon.

Onyx

Uses its own endpoint agents and browser extensions, so there is something new to roll out to devices.
No pricing published, and specific coding agents are not named on the pages we read.

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